#include <iostream>
using namespace std;
namespace wd{
int num=100;
void func(){
    cout<<"func"<<endl;
}
namespace cpp{
int num=200;
void func(){
    cout<<"cpp::func"<<endl;
}
}
}
void test0(){
    cout<<wd::cpp::num<<endl;
    wd::cpp::func();
}
void test1(){
    using namespace wd::cpp;
    cout<<num<<endl;
    func();

}
void test2(){
    using wd::cpp::num;
    using wd::cpp::func;
    cout <<num<<endl;
    func();
}
int main(int argc, char * argv[]){
    test0();
    test1();
    test2();

    return 0;
}

